Quick research....
In the 2016 draft, three of the top 10 picks were college hitters from major programs. Two, Corey Ray (5/MIL) and Zack Collins (10/CWS) started at high-A. One, Nick Senzel (2-CIN) started in low-A. Senzel tore up that league, and he's now in AA after a strong first half in the high-A FSL this year.
In the 2015 draft, four of the top 10 picks were college hitters from major programs. Top pick overall Dansby Swanson (ARI) started in short-season ball. Second overall Alex Bregman (HOU) split between low-A and high-A. Seventh overall Andrew Benintendi of BOS (sometimes a Haseley comp) started in the NY-Penn and finished in the SAL. Finally, at 9th overall Ian Happ of the Cubs started in short-season A and finished in low-A. Interestingly, all 4 of these guys are now in MLB barely two years after being drafted. Swanson is struggling a bit, but the others are holding their own or better.
What does this mean, to me? Well, I'd hope Haseley puts in a good 4-6 weeks at Williamsport and finishes up in Lakewood the last 3-4 weeks of the season. I don't see any problem with him playing alongside Moniak. One reason is, his development as a hitter will probably warrant it. Two, I don't think Haseley is the Phillies' center fielder when this team contends again. It could be Herrera, could maybe be Altherr, could be Moniak, or how about Mike Trout!!! Put Haseley in right field and let him be, if he earns a promotion to Lakewood.